• See Muizon and de Vries (1985). Basal most Pliocene. A tuff layer from the Sacaco level, above the Sud-Sacaco level, has been dated radiometrically (K/Ar) to 3.9 Myr (de Muizon & Bellon, 1980, 1986). Ehret et al (2012) updated the age to Messinian (5.93 Sr isotopes) rather than Zanclean.